Dealing with API in R

Full script:

http://pastebin.com/74tpbMzR

Declaring encoding and variables

# -*- coding: utf-8 -*-

Go to kimonolabs.com, login and get your own credentials

api.name <- '1xl232p8'
api.key <- 'DTndIua4tfpz5kxITOILI6FvmGV8xw9g'

Install required packages

install.packages("RCurl", "rjson")

And load them

library(RCurl)
library(rjson)

json.url <- paste0('https://www.kimonolabs.com/api/', api.name, '?apikey=', api.key)
json.url

[1] "https://www.kimonolabs.com/api/1xl232p8?apikey=DTndIua4tfpz5kxITOILI6FvmGV8xw9g"

json.file <- getURL(json.url, .encoding = 'UTF-8')
json.data <- fromJSON(json.file)

$name
[1] "RIA Lenta"

$count
[1] 20

$frequency
[1] "Every 15 mins"

$version
[1] 81

$newdata
[1] FALSE

$lastrunstatus
[1] "success"

$thisversionrun
[1] "Fri Oct 30 2014 06:10:49 GMT+0000 (UTC)"

$lastsuccess
[1] "Fri Oct 30 2014 06:25:59 GMT+0000 (UTC)"

$nextrun
[1] "Fri Oct 30 2014 06:40:59 GMT+0000 (UTC)"

$results

# seconds since epoch
as.POSIXct()

# list of parameters
as.POSIXlt()

# Date only
as.Date()

# Convert strings to datetime
strptime(x, format)

# get element from POSIXlt
# sec, min, hour, mday, mon, years, wday, yday

# Specify format
strftime(x, format)
# formats:
# %Y, %m, %d, %b, %H, %M, %S...

# tiemdelta: in seconds:
Sys.time() - 3600

s <- 'This is my test string'
substr(s, 6, 7)

[1] "is"

strsplit(s, ' ')

[[1]]
[1] "This"   "is"     "my"     "test"   "string"

tolower(s)

[1] "this is my test string"

Simple usage:

grep(pattern, x)

Complicated:

grep(pattern, x, ignore.case = FALSE, value = FALSE,
     fixed = FALSE, invert = FALSE)

head(airquality)

  Ozone Solar.R Wind Temp Month Day
1    41     190  7.4   67     5   1
2    36     118  8.0   72     5   2
3    12     149 12.6   74     5   3
4    18     313 11.5   62     5   4
5    NA      NA 14.3   56     5   5
6    28      NA 14.9   66     5   6

library(reshape2)
long <- melt(airquality, id.vars=c('Month', 'Day'))
head(long)

  Month Day variable value
1     5   1    Ozone    41
2     5   2    Ozone    36
3     5   3    Ozone    12
4     5   4    Ozone    18
5     5   5    Ozone    NA
6     5   6    Ozone    28

wide <- dcast(long, Month + Day ~ variable)
head(wide)

  Month Day Ozone Solar.R Wind Temp
1     5   1    41     190  7.4   67
2     5   2    36     118  8.0   72
3     5   3    12     149 12.6   74
4     5   4    18     313 11.5   62
5     5   5    NA      NA 14.3   56
6     5   6    28      NA 14.9   66